I just installed a new C97 and updated to the latest software revision. Currently on my network I have a pair of Lowrance EP-65 fuel level monitors and a pair of Fox Marine MEFI-3 engine interface modules. All components appear to be playing nicely with each other, The C97 displays the engine data from the engine modules and I get the fuel level data in % from the EP-65's. My problem is the C97 will not display total fuel volume. When I customize the fuel data page to show total fuel volume it displays nothing. I have set up the boat details in the C97 - two engines and two fuel tanks. I have set up total fuel for the boat at 225 gallons. I would think in order to get the total volume display I would have to tell the C97 the size of each individual tank. I haven't found that.

When I set the C97 to display Estimated fuel remaining and set the tanks to full fuel page will correctly display 225 gallons and then subtract fuel as the engines run.

I would rather have it display total volume so I do not have to estimate the fuel used by the generator and subtract it from the estimate fuel remaining.

The LightHouse II software is designed to merely report tank level as a percentage using data from PGN 127505. It sounds as though you may be incorrectly assuming that Total Fuel (vol) is calculated by multiplying the percentage of fuel within the tank by the tank's volume. The Total Fuel (vol) data item is instead dependent upon data from PGN 127497 Engine Trip Parameters. Should this PGN not be supplied by your system, then the Fuel Manager setup may be configured to calculate Est. Total Fuel Remaining based upon fuel consumption rate data ... should this be available within the system. Should the MFD be used to calculate fuel consumption, then it will only provide estimated fuel values, as it possible for the engines to be operated while the marine electronics remain OFF, leaving fuel consumed during such periods as unaccounted for.